This invention relates to an automatic transmission to attain four forward speeds and one reverse speed by combination of engagements and disengagements of five friction engagement elements by using Ravigneaux planetary gear set.
U.S. Pat. No. 5,951,433 (corresponding to Japanese Patent Application Publication No. 10-169730) discloses an automatic transmission arranged to attain four forward speeds and one reverse speed by combination of engagements and disengagements of two clutches and three brakes by using Ravigneux planetary gear set which is a compound type planetary gear set constituted by integrating two planetary gear trains, as shown in FIGS. 9(a) and 9(b) of the patent document.